The sequence of some regular proteins, together with other structural information such as data from x-ray diffraction, fiber diffraction, electron microscopy, and spectroscopic analysis can be used to evaluate models of protein structure. Four current studies involve keratin and other intermediate filaments (with NIADDK, NCI), actin (with NIADDK), streptococcal M5 protein (with Rockefeller University), and models of branched polymers (with PSL, DCRT).